Organic light emitting diodes displays and manufacturing method thereof

ABSTRACT

A cracks propagation preventing, polarization film attaches to outer edges of a lower inorganic layer of an organic light emitting diodes display where the display is formed on a flexible substrate having the lower inorganic layer blanket formed thereon. The organic light emitting diodes display further includes a display unit positioned on the inorganic layer and including a plurality of organic light emitting diodes configured to display an image, and a thin film encapsulating layer covering the display unit and joining with edges of the inorganic layer extending beyond the display unit.

RELATED APPLICATIONS

This application claims priority to and the benefit of Korean PatentApplication No. 10-2013-0063509 filed in the Korean IntellectualProperty Office on Jun. 3, 2013, the entire contents of whichapplication are incorporated herein by reference.

BACKGROUND

1. Field of Disclosure

The here described technology relates generally to an organic lightemitting diodes display (OLEDD), and more particularly, to an organiclight emitting diodes display having a planarization film, and amanufacturing method thereof.

2. Description of Related Technology

In an organic light emitting diodes display, a pixel circuit and anorganic light emitting diode (OLED) are disposed at every pixel area ona substrate, and light emitted from the plurality of organic lightemitting diodes is combined to display an image. If the organic lightemitting diodes display uses a polymer film as its substrate it may havea bending characteristic. In such a case it includes a flexible thinfilm encapsulating layer to encapsulate the organic light emittingdiodes. The flexible thin film encapsulating layer is susceptible tocracking when exposed to external impacts.

During mass production fabrication, the pixel circuits, the organiclight emitting diodes, and various wirings may be simultaneously formedwhile forming a plurality of display panels (referred to as unit cells)on a mother substrate, and then the monolithically integrated displaypanels are separated into individual unit cells by cutting the mothersubstrate. In this case, each unit cell is divided into a display areain which the pixel circuits and the organic light emitting diodes arepositioned, and into a pad area in which pad electrodes are positioned.

Particularly, in one mass production method of manufacturing the organiclight emitting diodes display, the process may include the steps of (1)forming the plurality of unit cells on the mother substrate, (2) formingthe thin film encapsulating layer on the display area of each unit cell,(3) attaching a passivation film to an entire upper portion of themother substrate, (4) separating the mother substrate into theindividual unit cells by cutting the mother substrate, (5) removing aportion of the passivation film corresponding to the pad area; (6)performing an examination after removing the portion corresponding tothe pad area in the passivation film, (7) removing the passivation filmof the unit cells that are determined from the examination to benon-defective product and (8) attaching a polarization film to suchnon-defective product.

The aforementioned organic light emitting diodes display has a verycomplicated manufacturing process, and thus is difficult to mass producewith consistency and minimized defects. Further, in the process, apartial area of an inorganic layer (a barrier layer, a buffer layer, andthe like) formed on the substrate may not be covered with the thin filmencapsulating layer and the polarization film and thus it is exposed.When an external impact is applied to the exposed inorganic layer,cracks can easily occur, and the cracks are propagated into the displaypanel, thereby causing a contagious defect that can spread across theorganic light emitting diodes displays of the mother substrate.

It is to be understood that this background of the technology section isintended to provide useful background for understanding the heredisclosed technology and as such, the technology background section mayinclude ideas, concepts or recognitions that were not part of what wasknown or appreciated by those skilled in the pertinent art prior tocorresponding invention dates of subject matter disclosed herein.

SUMMARY

The described technology has been made in an effort to provide anorganic light emitting diodes display capable of simplifying amanufacturing process and preventing a contagiously spread defect bysuppressing an occurrence of cracks due to an exposure of an inorganiclayer to crack inducing impacts.

A cracks propagation preventing, polarization film attaches to outeredges of a lower inorganic layer of an organic light emitting diodesdisplay where the display is formed a on a flexible substrate having thelower inorganic layer blanket formed thereon. The organic light emittingdiodes display further includes a display unit positioned on and withinan interior area of the inorganic layer and including a plurality oforganic light emitting diodes configured to display an image, and a thinfilm encapsulating layer covering the display unit and joining withexterior edges of the inorganic layer that extend beyond the displayunit.

More specifically, an exemplary organic light emitting diodes display,includes a flexible substrate, an inorganic layer formed on an entireupper surface of the substrate, a display unit positioned on and in aninterior portion of the inorganic layer and including a plurality oforganic light emitting diodes to display an image, a thin filmencapsulating layer fully covering the display unit and extending toattach to outer edges of the inorganic layer, and a polarization filmattached to and fully coveting the thin film encapsulating layer andextending to attach to yet further outer edges of the inorganic layerthat are at an exterior side of the thin film encapsulating layer.

A pads area may be positioned at an exterior side of the display unit onthe substrate, and the polarization film may be attached on the entireremaining areas over the substrate, except for the pads area which isexposed to allow for electrical testing. The polarization film mayinclude one edge, which is in contact with the pads area, and threeedges, which are matched with edges of the substrate. The substrate maybe formed of a polymer film, and the inorganic layer may include atleast one of a barrier layer and a buffer layer.

The disclosure provides a method of manufacturing an organic lightemitting diodes display, including forming an inorganic layer to fullycover a flexible mother substrate, forming a plurality of spaced apartdisplay units on the inorganic layer so as to form a matrix of unitcells, forming spaced apart thin film encapsulating layers at upperportions of the corresponding matrix of display units, respectively,attaching a polarization film exposed portions of the inorganic layer soas to also thereby fully cover the plurality of thin film encapsulatinglayers (while leaving exposed the pads areas so as to allow forelectrical testing of the plural pads areas); and separating theplurality of unit cells into individual unit cells by cutting the mothersubstrate and the polarization film.

The flexible mother substrate may be formed of a polymer film, and eachof the plurality of unit cells may include a pads area at an exteriorside of the display unit. The plurality of unit cells may be disposed asrows extending in two directions crossing each other, and each of theplurality of display units and the plurality of pad areas may bedisposed in a row in one direction between the two directions.

The polarization films having the same number as that of the mothersubstrates may be provided, and may be provided with openings throughwhich the plurality of pads areas is exposed. The polarization films maybe provided with slit-shaped openings parallel to the one direction tosimultaneously expose the plurality of pad areas positioned in the onedirection. One row of pad areas among the plurality of pad areas may bepositioned at an exterior side of one side edge of the polarizationfilm.

In the meantime, the polarization films may be formed in rod shapesparallel to the one direction to cover one row of thin filmencapsulating layers positioned in parallel to the one direction amongthe plurality of thin film encapsulating layers. The one side edge ofthe polarization film may be in contact with a boundary of the pad areatoward the display unit, and an opposite side edge may be positioned atan exterior side of the edge of the thin film encapsulating layer.

The polarization film in the individual unit cells may be positioned onthe thin film encapsulating layer and in contact with the outer edges ofthe inorganic layer that extend beyond the exterior sides of the thinfilm encapsulating layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an organic light emitting diodes displayaccording to an exemplary embodiment.

FIG. 2 is a cross-sectional view of the organic light emitting diodesdisplay taken along line A-A of FIG. 1.

FIG. 3 is an enlarged cross-sectional view of a display unit and a thinfilm encapsulating layer illustrated in FIG. 2.

FIG. 4 is a process flowchart illustrating a method of manufacturing theorganic light emitting diodes display according to an exemplaryembodiment.

FIGS. 5, 6, and 7 are perspective views illustrating a mother substratewith plural ones of the organic light emitting diodes displays in thesecond step, the third step, and the fourth step illustrated in FIG. 4,respectively.

FIG. 8 is a perspective view illustrating a first exemplary variation ofa polarization film illustrated in FIG. 7.

FIG. 9 is a perspective view illustrating a second exemplary variationof the polarization film illustrated in FIG. 7.

FIG. 10 is a top plan view illustrating the organic light emittingdiodes displays in the fifth step illustrated in FIG. 4.

DETAILED DESCRIPTION

The present disclosure of invention will be described more fullyhereinafter with reference to the accompanying drawings, in whichexemplary embodiments are shown. As those skilled in the art wouldrealize in light of this disclosure, the described embodiments may bemodified in various different ways, all without departing from thespirit or scope of the present teachings.

Unless explicitly described to the contrary, the word “comprise” andvariations such as “comprises” or “comprising”, will be understood toimply the inclusion of stated elements but not the exclusion of anyother elements. Further, it will be understood that when an element suchas a layer, film, region, or substrate is referred to as being “on”another element, it can be directly on the other element or interveningelements may also be present. Further, in the specification, the word“on” means positioning on or below the object portion, but does notessentially mean positioning on the upper side of the object portionbased on a gravity direction.

FIG. 1 is a perspective view of an organic light emitting diodes displayaccording to an exemplary embodiment. FIG. 2 is a cross-sectional viewof the organic light emitting diodes display taken along line A-A ofFIG. 1.

Referring to FIGS. 1 and 2, an organic light emitting diodes display 100includes a substrate 10, and a display unit 20, a thin filmencapsulating layer 30, and a polarization film 40 which are formed onthe substrate 10 substantially in the recited order.

The substrate 10, which is a flexible film, may be formed of atransparent or opaque polymer film (for example, polyimide). Thesubstrate 10 is subdivided into a display area DA and a pads area PA.The pads area PA is in contact with an edge of one side of the substrate10, and with wirings extending into the display area DA. The pads areaPA is positioned so as to leave a predetermined distance from the edgeof the substrate 10 to the remaining areas of the substrate 10, exceptfor the pad area PA.

The display unit 20 includes a plurality of organic light emittingdiodes and a plurality of pixel circuits that are positioned in thedisplay area DA. At least one organic light emitting diode (OLED) and acorresponding pixel circuit are provided for each pixel. The displayunit 20 displays an image by combining lights emitted from the pluralityof organic light emitting diodes.

Pad electrodes 11 are connected by way of integrally extendingconductors to the respective pixel circuits of the display unit 20. Thepad electrodes 11 are positioned in the pads area PA. In one embodiment,the pad electrodes 11 are not only connected to the circuitry under theencapsulating layer 30 but also to external further circuitry such as achip on film control circuit and/or an external printed circuit board,which are not illustrated. In other words, the pad electrodes 11 receivecontrol and/or data signals from the external further circuitry for usein driving the pixels of the display area 20 (DA). Alternatively oradditionally, one or more on-board integrated circuit chips (notillustrated) may be positioned in the pads area PA for serving as scanline drivers and/or data line drivers that respectively drive pluralscan lines and plural data lines provided under the encapsulating layer30.

It is to be observed that in the cross sectional view of FIG. 2, thethin film encapsulating layer 30 joins directly at its ends with anunderlying inorganic layer 18 so as to thereby fully and protectivelyencapsulate the display unit 20.

FIG. 3 is an enlarged cross-sectional view of the display unit 20, thethin film encapsulating layer 30 and the inorganic layer 18 where theinorganic layer is comprised of sublayers 12 and 13 (also referred toherein as layers 12 and 13).

Referring to FIG. 3, sublayer 12 serves as a barrier layer 12 andsublayer 13 serves as a buffer layer 13. These thin film sublayers, 12and 13 are deposited on the entire upper surface of the flexiblesubstrate 10 and are configured to flex with the flexible substrate 10.The barrier layer 12 includes a plurality of different and relativelythin inorganic layers, and may be formed in a structure in which, forexample, an SiO₂ layer and an SiNx layer are alternately and repeatedlystacked so as to provide flexibility and impermeability to oxygen and/orother corrosive materials (e.g., H2O). The barrier layer 12 has asubstantially smaller moisture transmission rate and a substantiallysmaller oxygen transmission rate than those of the polymer substrate 10.Thus the barrier layer 12 inhibits or prevents moisture and oxygen thatpermeates through the flexible polymer substrate 10 from furtherpermeating inwardly so as to damage the pixel circuits and theircorresponding organic light emitting diodes 50.

The buffer layer 13 is also formed of an inorganic layer, and mayinclude, for example, a planarized SiO₂ or SiNx layer. The buffer layer13 provides a flat dielectric surface for forming thereon the pixelcircuit, and it also suppresses moisture and foreign substances frompermeating inwardly to attack the pixel circuits and their correspondingorganic light emitting diodes 50.

One or more thin film transistors such as the exemplary TFT 60 and oneor more capacitors such as the exemplary Cst 70 are provided asencapsulated between the thin film encapsulating layer 30 and theinorganic layer 18 (comprised of sublayers 12 and 13) for forming acorresponding pixel circuit. The thin film transistor 60 includes asemiconductive layer 61, a gate electrode 62, and source/drainelectrodes 63 and 64. The semiconductive layer 61 may be formed of oneof a polysilicon or of a semiconductive oxide, and it includes a channelarea 611 in which an impurity is not heavily doped, and source/drainareas 612 and 613 in which one or more conductivity providing impuritiesare doped at both sides of the channel area 611. When the semiconductivelayer 61 is formed of the semiconductive oxide, a separate passivationlayer (not shown) for protecting the semiconductive layer 61 may beadded.

A gate insulating layer 14 is positioned between the semiconductivelayer 61 and the gate electrode 62, and an interlayer insulating layer15 is positioned between the gate electrode 62 and the source/drainelectrodes 63 and 64. The gate insulating layer 14 and the interlayerinsulating layer 15 may be formed of an organic material or an inorganicmaterial, such as SiO₂ and SiNx.

The capacitor 70 includes a first plate capacitor 71 formed on the gateinsulating layer 14, and a second plate capacitor 72 formed on theinterlayer insulating layer 15. The first plate capacitor 71 may beformed of the same material as that of the gate electrode 62, and thesecond plate capacitor 72 may be formed of the same material as those ofthe source/drain electrodes 63 and 64. The second plate capacitor 72 maybe connected with the source electrode 63.

The thin film transistor 60 illustrated in FIG. 3 functions as an OLEDdriving film transistor. Although not shown, and the pixel circuit mayfurther include a switching thin film transistor for selectivelycoupling a signal on an adjacent data line to the OLED drivingtransistor 60. In other words, the switching thin film transistor isused as a switching element for selecting a pixel that is desired to bemade to emit a certain predetermined magnitude of light, and the drivingthin film transistor applies power for making the OLED 50 of theselected pixel emit that predetermined magnitude of light.

A planarizing layer 16 is positioned on the source/drain electrodes 63and 64 and the second plate capacitor 72. The planarizing layer 16 isformed of an organic material or an inorganic material, or a complexform of an organic material and an inorganic material. An acryl-basedresin, an epoxy resin, a phenol resin, a polyamide-based resin and thelike may be used as the organic material. The planarizing layer 16 isprovided with a via hole through which a part of the drain electrode 64communicates to connect with the organic light emitting diode 50 that isformed on the planarizing layer 16.

The organic light emitting diode (OLED) 50 includes a pixel electrode51, an organic emission layer 52, and a common electrode 53. The pixelelectrode 51 is individually formed at each pixel, and is connected withthe drain electrode 64 of the thin film transistor 60 through the viahole. The common electrode 53 is formed of a light-passing material(e.g., ITO) and extends over the entire display area DA. A pixelbordering/defining layer 17 is positioned on the pixel electrode 51. Thepixel defining layer 17 is provided with an opening through which thepixel electrode 51 is exposed, and the organic emission layer 52 isformed at the opening to be in contact with the pixel electrode 51. Thepixel defining layer 17 may be formed of an opaque material.

The organic emission layer 52 may be any one of a red emission layer, agreen emission layer, and a blue emission layer. On the other hand, theorganic emission layer 52 may be a white emission layer, or a stackedlayer of the red emission layer, the green emission layer, and the blueemission layer. In a latter case, the organic light emitting diodesdisplay 100 may further include one or more color filters (notillustrated). The color filters may include a red filter correspondingto a red pixel, a green filter corresponding to a green pixel, and ablue filter corresponding to a blue pixel.

One of the pixel electrode 51 and the common electrode 53 serves as ananode which is a hole injection electrode, and the other serves as acathode which is an electron injection electrode. Holes injected fromthe anode and electrons injected from the cathode are combined in theorganic emission layer 52 to generate photons and thus light emission isperformed when paired combinations (excitons) of combining holes andelectrons join and discharge their combined energy.

At least one of a hole injection layer and a hole transport layer may bepositioned between the anode and the organic emission layer 52, and atleast one of an electron injection layer and an electron transport layermay be positioned between the organic emission layer 52 and the cathode.The hole injection layer, the hole transport layer, the electrontransport layer, and the electron injection layer may be formed on theentire display area DA without distinction as to which pixel they belongto.

The pixel electrode 51 may be a reflective electrode, while the commonelectrode 53 is a transflective (and thus resonance creating) or atransmissive electrode. The pixel electrode 51 may be a single layer ora multilayer containing at least one of aluminum (Al), gold (Au), silver(Ag), magnesium (Mg), lithium (Li), and calcium (Ca). The commonelectrode 53 may contain any one of an indium-tin oxide (ITO), anindium-zinc oxide (IZO), a zinc oxide (ZnO), and an indium oxide(In₂O₃).

Light emitted from the organic emission layer 52 is reflected from thepixel electrode 51, penetrates the common electrode 53, and then isdischarged to the outside for perception by a user. In a case where thecommon electrode 53 is the transflective type, some of the light raysare reflected to the pixel electrode 51 from the common electrode 53again to thereby form a resonant optics structure.

The thin film encapsulating layer 30 is positioned on the plurality oforganic light emitting diodes 50. The thin film encapsulating layer 30encapsulates the organic light emitting diodes 50 from an externalenvironment containing moisture and oxygen to suppress deterioration inthe organic light emitting diodes 50 due to exposure to moisture and/oroxygen. The thin film encapsulating layer 30 may be formed of aconfiguration in which a plurality of organic layers and a plurality ofinorganic layers are alternately stacked one by one so as to provideflexibility.

The organic layer of the thin film encapsulating layer 30 is formed ofpolymer, and may be a single layer or a stacked layer formed of any oneof, for example, polyethyleneterephthalate, polyimide, polycarbonate,epoxy, polyethylene, and polyacrylate. The inorganic layer of the thinfilm encapsulating layer 30 may be a single layer or a stacked layercontaining a silicon oxide or a silicon nitride, a metal oxide or ametal nitride. For example, the inorganic layer may contain any one ofSiNx, Al₂O₃, SiO₂, and TiO₂.

Referring to FIGS. 1 to 4, a polarization film 40 is attached on anexterior surface of the thin film encapsulating layer 30, and suppressesexternal light reflection which might be induced by nonplanar structureswithin the display area (DA), thereby improving visibility of thedisplay unit 20.

To reiterate, he inorganic layer 18 (see FIGS. 1 and 2) on the substrate10 is formed on the entire upper surface of the substrate 10 to have thesame width as that of the substrate 10. In this case, the inorganiclayer 17 includes at least one of the aforementioned battier layer 12and buffer layer 13. The display unit 20 is disposed to be spaced apartfrom the edge of the substrate 10 toward an inner side of the substrate10. The thin film encapsulating layer 30 is formed to have a larger areathan that of the display unit 20 and to thus; in combination with theinorganic layer 18 (i.e. layers 12-13) encapsulate the display unit 20.The thin film encapsulating layer 30 is also disposed to be spaced apartfrom the edge of the substrate 10 toward the inner side of the substrate10.

Additionally, the polarization film 40 is formed on the entire remainingareas of the substrate 10, except for the pad area PA. That is, thepolarization film 40 is formed to have the same size as those of theremaining areas of the substrate 10, except for the pad area PA. Inother words, three edges except for one edge of the four-edgedpolarization film 40 (where the one exception is the edge which is incontact with the pad area PA) are matched with the edges of thesubstrate 10 after the display cell unit is separated from its mothersubstrate. Accordingly, the inorganic layer 18 at an exterior side ofthe display unit 20 is covered with the polarization film 40 in theremaining areas of the substrate 10, except for the pad area PA, so thatthe inorganic layer 18 is not exposed to scratching or crack-inducingimpacts from the outside.

The polarization film 40 covers and protects the inorganic layer 18 ofthe exterior side of the display unit 20, thereby blocking most of theexternal impact applied to the inorganic layer 18 in a process ofmanufacturing the organic light emitting diodes display 100 and aprocess of assembling the organic light emitting diodes display 100 withother components after the manufacturing.

Accordingly, the polarization film 40 suppresses an occurrence of cracksof the inorganic layer 18, and even though the cracks occur in theinorganic layer 18 due to the external impact applied from a sidesurface, the polarization film 40 may block the cracks from beingfurther propagated with the display unit 20 or to further display unitsof a common mother substrate. As a result, a contractible defect of theorganic light emitting diodes display 100 according to the propagationof the cracks to the display unit 20 may be prevented or its spreadreduced.

FIG. 4 is a process flowchart illustrating a method of manufacturing theorganic light emitting diodes display according to the exemplaryembodiment.

Referring to FIG. 4, the method of manufacturing the organic lightemitting diodes display includes: (1) a first step S10 of forming aninorganic layer on and over the whole surface of a mother substrate, (2)a second step S20 of forming a plurality of display units on theinorganic layer so as to form a plurality of unit cells, and (3) a thirdstep S30 of forming a thin film encapsulating layer at an upper portionof each of the plurality of display units. Further, the method ofmanufacturing the organic light emitting diodes displays on a mothersubstrate includes (4) a fourth step S40 of attaching a polarizationfilm on the inorganic layer so as to cover a plurality of thin filmencapsulating layers, and (5) a fifth step S50 of separating theplurality of unit cells into individual unit cells by cutting the mothersubstrate and the polarization film.

FIG. 5 is a perspective view illustrating the organic light emittingdiodes display in the second step illustrated in FIG. 4.

Referring to FIGS. 1 and 5, the inorganic layer 18 is blanket-formed(e.g., blanket deposited) on an entire upper surface of a mothersubstrate 110 (e.g., one formed of a base polymer). The inorganic layerincludes at least one of the barrier layer 12 and the buffer layer 13.

The flexible mother substrate 110 of the first step S10 and the secondstep S20 is supported by a rigid carrier substrate (not illustrated) tomaintain a flat state in a process of forming the inorganic layers 18and the display units 20. The carrier substrate may be a glasssubstrate, and the flexible mother substrate 110 may be formed by amethod of spin coating a polymer material on the glass carrier substrateand curing the polymer material. The carrier substrate is separated fromthe mother substrate 110 after forming the thin film encapsulating layer30 or attaching the cracks-suppressing polarization film 40.

The mother substrate 110 has a size sufficient for including apredetermined number of plural unit cells 120, and the plurality of unitcells 120 is positioned in parallel in a first direction (x-axisdirection) and a second direction (y-axis direction) crossing the firstdirection of the mother substrate. Each unit cell 120 includes arespective display area DA and a respective pads area PA. The displayunits 20 including the plurality of pixel circuits and the plurality oforganic light emitting diodes are positioned in the display area DA. Thepad electrodes (not illustrated) are connected with the respective pixelcircuits and are positioned in the pads area PA.

One or more integrated circuit chips (e.g., scan lines driving chipand/or data lines driving chip) may be mounted in the pads area PA inthe second step S20 or may be mounted in the pads area PA after thefifth step S50. In FIG. 5, a case where the display unit 20 and the padsarea PA are adjacent in the first direction (x-axis direction) isillustrated as an example.

FIG. 6 is a perspective view illustrating the organic light emittingdiodes display in the third step illustrated in FIG. 4.

Referring to FIG. 6, here the thin film encapsulating layer 30 has beenformed at the upper portion of each of the plurality of display units120 in the third step S30. The thin film encapsulating layer 30 isformed by a method in which the plurality of organic layers and theplurality of inorganic layers are alternately and repeatedly stacked oneby one, and is formed to have a larger area than that of the respectivedisplay unit 120 to cover the edges of the display units 120 and to joinwith a part of the blanket-formed inorganic layer 18 (see FIG. 2) tothereby individually encapsulate each respective display unit 20 (DA).

FIG. 7 is a perspective view illustrating the organic light emittingdiodes display in the fourth step illustrated in FIG. 4.

Referring to FIG. 7, here the polarization film 40 has been blanketformed on top of the plurality of thin film encapsulating layers 30 inthe fourth step S40. The polarization film 40 is one sheet ofpolarization film material corresponding to the full extent of themother substrate 110. After or during formation, the one sheet ofpolarization film 40 is provided with openings 41 as illustrated suchthat the respective plurality of pads areas PA are exposed and therespective display units 120 can be electrically tested. The one sheetof polarization film 40 simultaneously covers the whole of the thin filmencapsulating layers 30 formed on the mother substrate 110, and is incontact with the inorganic layer 18 at the exterior side of the thinfilm encapsulating layer 30 of each of the respective display units 120.

The plurality of pads areas PA are positioned in parallel in the seconddirection (y-axis direction) based on FIG. 7. The polarization film 40is provided with the slit-shaped openings 41 parallel to the seconddirection, to expose the plurality of pad areas PA positioned in thesecond direction by using one opening 41. The number of openings 41 maybe the same as the number of unit cells 120 positioned on the mothersubstrate in the first direction (x-axis direction).

FIG. 8 is a perspective view illustrating a first exemplary variation ofthe patterning of the polarization film as compared to the oneillustrated in FIG. 7.

Referring to FIG. 8, in the first exemplary variation, a modifiedpolarization film 401 covers the remaining areas of the mother substrate110, except for one row of pad areas PA (pad areas positioned at aright-side end (right side in the drawing) of the mother substrate basedon FIG. 8) positioned at an outermost side of the mother substrate 110.That is, the one row of pad areas PA are positioned at an exterior sideof an edge of one side of the polarization film 401. Thus, less materialmay be used for forming the modified polarization film 401 as comparedto the polarization film 400 of FIG. 7 which covers the entire mothersubstrate.

The polarization film 401 is provided with openings 41 for the remainingrows of pad areas PA, except for the aforementioned one row of pad areasPA, to expose the pad areas PA. The number of openings 41 of thepolarization film 401 in the first exemplary variation is the same asthe number subtracted by 1 from the number of unit cells positioned inthe first direction (x-axis direction). One sheet of the polarizationfilm 401 of the first exemplary variation also simultaneously covers thewhole of the plurality of thin film encapsulating layers 30 formed onthe mother substrate 110, and is in contact with the inorganic layer 18at the exterior side of the thin film encapsulating layer 30.

FIG. 9 is a perspective view illustrating a second exemplary variationof the polarization film as compared to the one 400 illustrated in FIG.7.

Referring to FIG. 9, plural polarization films 402 are deposited in rod(rectangular bar) shapes in the second exemplary variation. Theplurality of thin film encapsulating layers 30 are positioned inparallel in the second direction (y-axis direction) based on FIG. 9. Therod-shaped polarization films 402 simultaneously each covers onerespective row of the thin film encapsulating layers 30 positioned inthe second direction. Thus, less material may be used for forming thesecond modified polarization film 402 as compared to the polarizationfilm 400 of FIG. 7 which covers the entire mother substrate.

The number of rod-shaped polarization films 402 may be the same as thenumber of unit cells 120 positioned in the first direction (x-axisdirection) on the mother substrate 110. One side edge of thepolarization film 402 is in contact with the boundary of the pads areaPA toward the display area DA, and an opposite side edge thereof ispositioned at an exterior side of the edge of the thin filmencapsulating layer 30. That is, the polarization film 402 is formed tobe larger than the thin film encapsulating layer 30 to be in contactwith the inorganic layer 18 on the mother substrate 110.

FIG. 10 is a top plan view illustrating the organic light emittingdiodes display in the fifth step illustrated in FIG. 4.

Referring to FIG. 10, the mother substrate 110 in the fifth step S50 iscut (diced) along a first cutting line CL1 to be separated by a rod unitin which the plurality of unit cells 120 is connected in one direction.Then, the mother substrate 110 is cut along a second cutting line CL2 tobe separated into individual unit cells. The first cutting line CL1 isparallel to any one direction of the first direction (x-axis direction)and the second direction (y-axis direction), and the second cutting lineCL2 crosses the first cutting line CL1.

According to the aforementioned method of manufacturing the organiclight emitting diodes display 100, after the thin film encapsulatinglayer 30 is formed, the respective polarization film 40, 401, or 402 isattached instead of a passivation film. In this case, the plurality ofthin film encapsulating layers 30 may be simultaneously covered by usingone sheet or several sheets of polarization films 40, 401, or 402. Theattached polarization film (e.g., 40, 401, or 402) simultaneouslysuppresses crack formation and reduces perception of artifact lightsfrom internal reflections. Accordingly, it is possible to omit a processof attaching a passivation film and a process of removing thepassivation film, and it is possible to simplify a process of attachingthe polarization film which has been performed on each of the unit cells120.

Further, the polarization film 40, 401, or 402 covers and protects theinorganic layer 18 at the exterior side of the thin film encapsulatinglayer 30. Accordingly, the organic layer 18 at the exterior side of thethin film encapsulating layer 30 is not exposed to the outside duringthe entire manufacturing and assembling processes after the polarizationfilm 40, 401, or 402 is attached.

Accordingly, it is possible to suppress an occurrence of cracks in theinorganic layer 18 due to external impact, and even though the cracksoccur in one spot in the inorganic layer 18 due to the external impactapplied from the side surface, the cracks is not propagated to thedisplay units 120 of the mother substrate by the polarization film 40,401, or 402, thereby not causing a contagiously spread defect.

Whether the organic light emitting diodes display 100 after the fifthstep S50 is a non-defective product is determined through an inspectionprocess, and a process of assembling the chip on film and the printedcircuit board is performed on the organic light emitting diodes display100 which is determined as the non-defective product.

According to the present exemplary embodiment, it is possible tosuppress an occurrence of spreading cracks of the inorganic layer, andeven though the cracks may occur in one spot the inorganic layer, it ispossible to block the cracks from being propagated to the other displayunits of a shared mother substrate. Accordingly, it is possible toprevent a contractible defect according to the propagation of the cracksto the other display units. Further, it is possible to omit a process ofattaching a passivation film and removing the passivation film, and tosimplify a process of attaching the polarization film.

While this disclosure has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the present disclosure of invention is not limited tothe disclosed embodiments, but, on the contrary, is intended to covervarious modifications and equivalent arrangements included within thespirit and scope of the present teachings.

What is claimed is:
 1. An organic light emitting diodes display,comprising: a flexible substrate; an inorganic layer covering an entireupper surface of the flexible substrate; a display unit formed on afirst portion of the inorganic layer while leaving a second portionexposed, the display unit including a plurality of organic lightemitting diodes configured to display an image; a thin filmencapsulating layer covering the display unit formed on the firstportion of the inorganic layer while not covering most of the secondportion, but joining with inner boundary parts of the second portion ofthe inorganic layer so as to fully encapsulate the display unit; and apolarization film attached to and covering the thin film encapsulatinglayer and a portion of the inorganic layer extending beyond exteriorsides of the thin film encapsulating layer such that the polarizationfilm in combination with the inorganic layer fully encapsulates thecombination of the thin film encapsulating layer and the display unit.2. The organic light emitting diodes display of claim 1, wherein: a padsarea is positioned at an exterior side of the display unit and on thesecond portion of the inorganic layer, and the polarization film isattached to and covers the entire remaining areas of the inorganiclayer, except for the pads area.
 3. The organic light emitting diodesdisplay of claim 2, wherein: the polarization film includes one edge,which is in contact with an edge of the exposed pads area, and threeedges which are matched with edges of the remaining areas of theinorganic layer.
 4. The organic light emitting diodes display of claim1, wherein: the flexible substrate is formed of a polymer film, and theinorganic layer includes at least one of a barrier layer and a bufferlayer.
 5. A method of manufacturing an organic light emitting diodesdisplay, comprising: forming an inorganic layer on a mother substrate;forming a plurality of spaced apart display units on the inorganic layerso as to define a matrix of unit cells; forming spaced apart andrespective thin film encapsulating layers at upper portions ofrespective ones of the display units; attaching one or more polarizationfilms to the inorganic layer while at the same time covering all or acorresponding subset of the thin film encapsulating layers; andseparating the plurality of polarization film covered unit cells intoindividual unit cells by cutting the mother substrate and thepolarization film.
 6. The method of claim 5, wherein: the mothersubstrate is formed of a flexible polymer film, and each of theplurality of unit cells includes a pads area that is exposed at anexterior side of the display unit so as to be electrically contacted byexternal circuitry.
 7. The method of claim 6, wherein: the plurality ofunit cells is disposed in a row in two directions crossing each other,and each of the plurality of display units and the plurality of padsareas is disposed in a row in one direction between the two directions.8. The method of claim 7, wherein: openings are provided by the one ormore polarization films, the openings being substantially same in numberas that of rows of pads areas provided on the mother substrates, wherethe openings are ones through which the respective pluralities of padareas are exposed.
 9. The method of claim 8, wherein: the polarizationfilms are provided with slit-shaped openings parallel to the onedirection to simultaneously expose the plurality of pads areaspositioned in the one direction.
 10. The method of claim 9, wherein: onerow of pads areas among the plurality of pad areas are positioned at anexterior side of one outer side edge of the polarization film.
 11. Themethod of claim 7, wherein: for the case of more than one polarizationfilms, the polarization films are formed in rod shapes parallel to theone direction to cover one row of thin film encapsulating layerspositioned in parallel to the one direction among the plurality of thinfilm encapsulating layers.
 12. The method of claim 11, wherein:respective one side edges of the respective polarization films are eachs in contact with a boundary of the pads area that is toward the displayunit, and an opposite side edge thereof is positioned at an exteriorside of the edge of the thin film encapsulating layer.
 13. The method ofclaim 5, wherein: the polarization film in the individual unit cell ispositioned on the thin film encapsulating layer and on the inorganiclayer at an exterior side of the thin film encapsulating layer.